Air-based fryer

ABSTRACT

The present invention relates to food preparation. In order to provide an apparatus for preparing food of increased variance with improved cooking time and also improved food quality, a desk-appliance apparatus (10) for preparing food is provided, comprising a food preparation chamber (12), an air movement device (14), a heating device (16), and air guiding means (18). The food preparation chamber is provided by a container structure (22) at least partly enclosing a receiving volume (24) for receiving food to be prepared by a through-streaming of hot air; wherein the container structure comprises sidewalls (26) and a bottom wall (28), wherein the bottom wall and/or one of the side walls is air-permeable providing an air entry opening (30) for entering of hot air into the receiving volume, and wherein the container structure comprises an air discharge opening (32). The heating device is configured to heat air of an air flow provided by the air movement device. The air guiding means provide an air duct arrangement (34) from the discharge opening via the heating device and the air movement device to the air entry opening. The heating device is arranged out-of-sight of the receiving volume.

This application is the U.S. National Phase application under 35 U.S.C.§ 371 of International Application No. PCT/EP2014/060375, filed on May21, 2014, which claims the benefit of European Application No.13170419.9 filed on Jun. 4, 2013. These applications are herebyincorporated by reference herein.

FIELD OF THE INVENTION

The present invention relates to food preparation and relates inparticular to an apparatus for preparing food and a method for preparingfood.

BACKGROUND OF THE INVENTION

An example for an apparatus for preparing food is the Philips air-basedfryer, which is an appliance that can cook food, for example fries orchicken, with hot air. In order to heat the food for the preparation ofthe food, a flow of hot air is moved over the food to heat the same,respectively blown through the food containing volume for heatingpurposes. Such an appliance can be used, for example, in the householdenvironment. For providing the thermal energy to generate hot air, aheater is arranged in the flow path. For example, WO 2012/032449 A1describes an apparatus for preparing food with hot air, in particularstandard food such as French fries. However, it has been shown that evenan increasing range of food could be prepared in a food preparationappliance using hot air, but the operation is suitable primarily for thestandard French fries.

SUMMARY OF THE INVENTION

There may be a need to provide an apparatus for facilitated preparingfood of increased variance with improved cooking time and also improvedfood quality.

The object of the present invention is solved by the subject-matter ofthe independent claims, wherein further embodiments are incorporated inthe dependent claims. It should be noted that the following describedaspects of the invention apply also for the apparatus for preparing foodas well as for the method for preparing food.

According to the present invention, a desk-appliance apparatus forpreparing food is provided, comprising a food preparation chamber, anair movement device, a heating device, and air guiding means. The foodpreparation chamber is provided by a container structure at least partlyenclosing a receiving volume for receiving food to be prepared by athrough-streaming of hot air, wherein the container structure comprisesside walls and a bottom wall. The bottom wall and/or one of the sidewalls is air-permeable providing an air entry opening for entering ofhot air into the receiving volume. The container structure furthercomprises an air discharge opening. The heating device is configured toheat air of an air flow provided by the air movement device. The airguiding means provide an air duct arrangement from the discharge openingvia the heating device and the air movement device to the air entryopening. The heating device is arranged out-of-sight of the receivingvolume.

By arranging the heating device out-of-sight of the receiving volume, adirect path for heat radiation is prevented. Thus, convection is theprimarily source for the transfer of heat to the food to be prepared. Inother words, in combination with a higher airflow, a heater withincreased power, i.e. a heater with a higher heat transfer capability tothe air flow, can be provided for an improved heat transfer. Since theheater power is determined by the airflow (l/s), a higher air flow meansthat a higher power heater can be used without creating too much thermaldifferences between the lower and upper part of the food volume. Sincethe radiation from the top is prevented, i.e. blocked away, there is noneed to achieve the delicate balance between radiation and convectionany more. Thus, even in case of a user overfilling the appliance withfood, resulting in a lower air flow, although the food quality will belower than if it would be prepared with normal filling levels, a betterfood quality is provided compared to the case when the food is exposedto heater radiation. Even in case of a lower flow rate that results in ahigher heater temperature, since the heater is cooled less with a lowerflow rate, a proper heat distribution is ensured by providing theconvection as the only heat source for the food. For example, thetemperature of the air that is carrying the convection heat may bemeasured by a temperature measuring device. In case of a decreasingflow-rate, and therefore an increasing heater temperature, thetemperature measuring device may switch off the heater if the airtemperature reaches a too high, i.e. critical, level. In a situationwhere the heater is in direct line of sight of the heater, a higherheater temperature would only partially result in a higher airtemperature since only a part of the heat energy would be transported byconvection. Especially in the situation were the food is stillrelatively cold (at the beginning of the process), the overexposure toradiation would not be detected, because the food cools down the airstream. By arranging the heating device out-of-sight of the receivingvolume, this is prevented. This also considers the desire to prepare anincreasingly variable range of food, since different types of food wouldhave different possible flow-through rates. Since the radiation isomitted as a heat source, there is also no more need for a properbalance of radiation and convection. Thus, also the change of radiationemissivity of the heater during its lifetime is taken intoconsideration. In case of a decreasing power of the heater, simply anincreasing time for preparing the food would be needed. However, sincethere is no need to watch and regulate the proper balance betweenradiation and convection, the food quality is optimized.

The term “desk-appliance” refers to an apparatus that is suitable forhousehold purposes, which apparatus can be placed on different workingsurfaces in a kitchen of the table, or can be place in a shelf or on acupboard. The desk-appliance relates to an appliance that can bemanually moved and carried to different places by a single person. Forhousehold purposes the volume occupied by the appliance is constrainedto sizes as small as possible. In an example, the desk-appliance relatesto a portable appliance.

The term “air guiding means providing an air duct arrangement” relatesto an air duct for allowing a circulating airflow. This can be providedby specific air channels or air conduits. However, this can,alternatively or in addition, also be provided by a housing of theapparatus enclosing the different devices and/or elements. For example,the air guiding means comprise air duct segments in the vicinity of theair movement device, guiding the air from the air movement device to thefood preparation chamber and from there back to the air movement device.In another example, a rather strong fan as an air movement device isprovided inside the housing providing a circulating air flow, whereinthe housing provides the air duct. For example, the air movement deviceand the food preparation chamber are arranged such that a by-passingairflow of the food preparation chamber are prevented, e.g. the foodpreparation chamber is arranged close to an inner side-wall of thehousing, the air movement device is also arranged close to an innerside-wall of the housing, and the air movement device and the foodpreparation chamber are arranged close to each other.

The term “through-streaming of hot air” refers to the delivery of heatto the food to be prepared by the hot air. The air is not only reachingthe upper surface of a food pile, but reaches also interior spaces ofthe food piles, for example in a pile of French fries, which are alsoreferred to as chips in English, frites in French and Pommes Frites inGerman. The term “through-streaming of hot air” relates to hot airpenetrating food, i.e. food piles, also referred to as food accumulationor food cluster. Thus, the hot air is not only moved around the outerboundary of the food, but directly actually heats up, i.e. transmits theheat directly to places inside the outer boundary areas, such as insidea staple of food parts. Of course, besides French fries, also other foodwith a similar structure is provided, i.e. food in form of multiplesingle parts or portion provided in a piled, stapled or heaped manner.

Hence, the “through-streaming of hot air” provides not only heatdistribution throughout the food chamber, but also heat transfer toinner portions of the food.

In an example, the air flow is provided with a high velocity and inparticular with a high flow rate in the food preparation chamber. Forexample, an airflow rate of approximately minimum 20 l/sec is provided.

In an example, an airflow path is provided with minimal number ofchanges in the cross-section. For example, an airflow path is providedthat changes its cross-section only in a range of approximately maximum40% from the point where the air is exiting a ventilation device to thepoint where the air is entering the ventilation device again. In anotherexample, changes of the cross-section are provided in a range ofapproximately 20% maximum. Nozzles should be avoided.

In an example, a nozzle-free airflow path is arranged.

In an example, the apparatus for preparing food delivers heat to thefood to be prepared primarily by the hot air. In an example a one-wayheating is provided by the hot air, i.e. the hot air is the only heatsource affecting, or impacting on the food in the food preparationchamber.

The food preparation chamber provided by the container structure maycomprise an insert like a basket structure, for example with a meshstructure to insert food in a facilitated way, and also to take theprepared food out of the apparatus again after preparation. Thecontainer structure may also be removable for filling and emptyingpurposes as well as for cleaning purposes.

The heater only, or at least to a large extent, provides thermal energyin form of convection, i.e. in form of the hot air flow, and not byradiation. Thus, even with different food types and amounts, the heatsource i form of the hot air results in good and homogenous food qualityand also in short or at least minimized cooking times. Thus, anincreasing range of food can be prepared.

The term “out-of-sight” also comprises arrangements where the heater isplaced out of sight to an extent of for example 70% or more. In anexample, 90% are out-of sight.

For example, the heating device comprises one or more heating elementswith a heat-providing surface. Some portions of the heat-providingsurface are facing towards, i.e. in direction of the food preparationchamber. The following is meant by “out-of-sight”: Seen from the foodpreparation chamber, a major part of the heat-providing surfaces facingthe food preparation chamber is not visible, i.e. shielded. For example,if the heater would be replaced by light sources, only a little amountof the light providing surface would be seen from the food preparationchamber, or no light at all.

For example, the heat provided by the heating device is shielded orblocked from radiation towards the food. This provides an arrangementwhere heat, i.e. thermal energy is transferred to the food only (or atleast to the largest extent) by the hot air. Of course, hot air may alsoheat up an enclosure or side-walls, and these surfaces will thentransfer heat via radiation to the food. But this heat transmission isneglectable in relation to the heat transfer by the hot air. Forexample, the heat transfer via hot air, i.e. via convection is providedto be at least 70% of the thermal energy transfer to the food. In anexample, at least 80, e.g. minimum 90 or 95% of the heat is provided bythe hot air.

The term “out-of-sight” relates to the direct path of heat radiation.For example, the heat radiation path is independent from an opticalpath, i.e. non-related to a line of direct (visible) light. For example,radiated heat may pass through a filter or air distributing element,while it is not possible to look through the filter, i.e. the filter isnon-transparent. According to the example of the invention, the heateris arranged such that the heat that is radiated by the heating elements,for example hot surfaces, which are provided for convection of heat bythe air streaming passed the hot surfaces (the air streaming forced bythe air movement means, such as a ventilation device or fan), alsoprovide radiation. However, measures are provided that the radiated heatis not affecting the food in the food container. In an example, themeasures may comprise the arrangement of the heating elements on theside of food container, i.e. next to the outer side of the side wall ofthe container. The measures may comprise shielding elements to preventthe heat transfer of the radiation. For example, a container side wallmay be arranged between the heating element and the part of thecontainer volume arranged for receiving the food. In another example,separate protective elements are providing shielding for the heatradiation from the heating elements. In another example, the heatingelements are arranged such that they radiate heat only in a directionaway from the food.

According to an example, the heating device is arranged sidewards of thefood preparation chamber.

According to an example, the air movement device is a fan with an airinlet and an air outlet. The fan is provided sidewards of the foodpreparation chamber.

By providing the fan sidewards of the food preparation chamber, the airflow path is improved by arranging the fan closer to the air entryopening, where the most powerful air stream is needed for a proper anddistributed entering of hot air into the food to be prepared.

According to an example, as an air movement device, a fan is providedthat has an air suction side and an air blowout side. In use, the air isblown out at the air blowout side with a mean blowing direction, and themean blowing direction is provided with a tilted angle to both thehorizontal and the vertical.

This provides the advantage that the demand for guiding the air flowfrom the fan is reduced, since the air flow is already provided with atilted angle, and not in a perpendicular manner, hitting, for example,lower surfaces. This is also advantageous in that the air flow at theair blowout side may show the maximum air speed with regards the to thecirculating air flow path.

The mean blowing direction can be seen as the primary or main blowingdirection of the ventilated, i.e. moved air. However, since the actualblowing characteristic of an air stream is not directly visible, thefollowing is noted: In a quite general example, the fan comprises atleast one rotating part to move the air, such as a rotating blade, sothat an axis of rotation is provided. The rotation of air movementelements, such as blades or the like, results in a respective blowingdirection. For example, the air movement device can be provided as anaxial fan where a mean blowing direction is aligned with the axis ofrotation, for example parallel to the rotation axis. As another example,the air movement device can be provided as a centrifugal fan, alsoreferred to as a radial fan where a mean blowing direction is alignedwith a tangential line with regard to the rotating blade(s), wherein thetangential line is perpendicular to the rotating axis. Thus, thedirection of the rotating axis also determines the basic direction forthe air stream, e.g. parallel in case of an axial fan, or perpendicularin case of a centrifugal fan.

In an example, the axis of rotation is provided in a tilted angle withrespect to the horizontal and/or the vertical.

According to an example, the fan is a centrifugal fan inside a fanhousing with an axial air inlet and a radial air outlet. The centrifugalfan comprises a fan rotating in a rotating plane, and the rotating planeis provided with a tilted angle to both the horizontal and the vertical.

This provides the advantage that the air exiting the fan needs lessdeviation or air guidance than the air guidance taking place inside thefan. In other words, the approximately perpendicular change of directionof the air flow inside the fan is integrated into the air flow path suchthat an air stream towards the fan from the food preparation chamber isprovided with an angle larger than 90°, as well as the air exiting thefan shows a change of direction also with an angle larger than 90°before being applied to the food preparation chamber. The sharpest bentof the air flow path takes place in the fan itself. Since a sharp bentmeans an increased flow resistance for the air stream, the provision ofangles larger than 90° in flow stream areas with higher flow speed meansan advantage in terms of minimizing flow resistance for maximizing theflow. The provision of a rather sharp bent, or even the sharpest bent,inside the fan takes into consideration that the flow is influenced bythe fan blades anyhow here.

According to an example, the tilted angle comprises an angle to thehorizontal in a range of approximately 10° to 80°. For example, an angleof approximately 45° is provided.

It must be noted that a skilled person also understands that a solutionmay be provided that defers from these directions and which solutionprovides structural air guiding means.

The tilted arrangement also provides the advantage of a compact housing.

According to a further example, a first line is defined by the rotatingaxis, a second line is arranged perpendicular to the first line in therotating plane, and a third line is perpendicular to the bottom wall,running through a centre of the bottom wall. The first line, the secondline, and the third line are arranged in one plane and form a triangle.An inner circle of the triangle is arranged inside a housing structureof the apparatus. The first and the second line have an intersectionpoint that is arranged in a middle region of the height of the housingstructure. The inner circle has a maximum diameter.

According to a further example, an air duct arrangement comprises anumber of guiding portions, in which an air flow direction is changed. Afirst guiding portion is provided downstream, following the air movementdevice, and a second guiding portion is provided upstream in front ofthe air movement device. The first guiding portion provides a lowerdegree of change of direction of the air flow than the second guidingportion.

According to a further example, a collecting device with a collectingvolume is provided below the food preparation chamber for collectingresidual material.

Thus, it is provided to collect, for example, oils and particles on aspecific location in the removable pan of the appliance. Oils andparticles that come from the food will be blown to this location by thehot air that exits the fan system. After the cooking process, theconsumer can easily access this location for cleaning. This may lead tomore frequent cleaning and prevents oils to be burned into the surfacesby repeated heating. Further, it is also preventing obstruction of themost important air flow path in the appliance. This supports theappliance performance to be consistent during the use. Another aspect isthat the oil and particle volume may be located at a position where theair temperature is low enough to prevent smoking during the cookingprocess.

It is explicitly noted that, according to another aspect, the collectingdevice is provided in relation with features mentioned above, butwithout, for example, the tilted arrangement of the air movement deviceor the out-of-sight arrangement of the heating device. For example, anapparatus for preparing food is provided, comprising a food preparationchamber, an air movement device, a heating device, and air guidingmeans. The food preparation chamber is provided by a container structureat least partly enclosing a receiving volume for receiving food to beprepared by a through-streaming of hot air. The container structurecomprises side walls and a bottom wall. The bottom wall and/or one ofthe side walls is air-permeable, providing an air entry opening forentering of hot air into the receiving volume. The container structurefurther comprises an air discharge opening. The heating device isconfigured to heat air of an air flow provided by the air movementdevice. The air guiding means provide an air duct arrangement from thedischarge opening via the heating device and the air movement device tothe air entry opening. According to the other aspect, a collectingdevice with a collection volume is provided below the food preparationstructure for collecting residual material, e.g. oil and particles.

According to a further example, an air guiding element is provided thatdirects a horizontal air flow below the container structure in anupwards direction towards the air entry opening. The collecting deviceis arranged besides the air guiding element on a side facing away fromthe horizontal air flow.

According to a further example, an air distributing duct is providedbelow the air entry opening of the bottom wall. An air guide is providedas an elevation arranged on a lower surface of the air distributing ductbelow the air entry opening. The air guide is arranged in a skewedmanner in relation to a perpendicular direction of an out-blowingdirection of the air outlet such that below the air entry opening anevenly distributed air flow is provided.

For example, the elevation is extending across the cross-section of theair distributing duct. In an example, the elevation is extending acrossat least a third of the cross-section, for example in one section oralso in separated sections. In a further example, the elevation isextending across at least half of the cross-section. In a still furtherexample, the elevation is extending across the complete cross-section.

The skewed or rotated air guide converts the uneven air flow from thefan system in an air flow that is evenly distributed over the bottomsurface, for example of a food basket for receiving fries, for example.It must be noted that in the cross-sectional view, the rotation is notvisible.

It is explicitly noted that, according to a further aspect, the airdistributing duct is provided in relation with features mentioned above,but without, for example, the tilted arranged of the air movement deviceor the out-of-sight arrangement of the heating device. For example, anapparatus for preparing food is provided, comprising a food preparationchamber, an air movement device, a heating device, and air guidingmeans. The food preparation chamber is provided by a container structureat least partly enclosing a receiving volume for receiving food to beprepared by a through-streaming of hot air. The container structurecomprises side walls and a bottom wall. The bottom wall and/or one ofthe side walls is air-permeable providing an air entry opening forentering of hot air into the receiving volume. The container structurefurther comprises an air discharge opening. The heating device isconfigured to heat air of an air flow provided by the air movementdevice. The air guiding means provide an air duct arrangement from thedischarge opening via the heating device and the air movement device tothe air entry opening. According to a further aspect, an airdistributing duct is provided below the air entry opening of the bottomwall, wherein an air guide is provided as an elevation arranged on alower surface first the air distributing duct below the air entryopening. The air guide is arranged in a skewed manner in relation to aperpendicular direction of an out-blowing direction of the air outletsuch that below the air entry opening, an evenly distributed air flow isprovided.

For example, the elevation is extending across the cross-section of theair distributing duct. In an example, the elevation is extending acrossat least a third of the cross-section, for example in one section oralso in separated sections. In a further example, the elevation isextending across at least half of the cross-section. In a still furtherexample, the elevation is extending across the complete cross-section.

According to a further example, a flow spreader is provided between theair outlet and an air distribution zone provided below the air entryopening of the bottom wall. The flow spreader is provided as a ductsegment with a decreasing cross-section across an air passage directionto compensate for an asymmetrical air output of the air outlet.

It is explicitly noted that, according to a still further aspect, theflow spreader is provided in relation with features mentioned above, butwithout, for example, the tilted arrangement of the air movement deviceor the out-of-sight arrangement of the heating device. For example, anapparatus for preparing food is provided, comprising a food preparationchamber, an air movement device, a heating device, and air guidingmeans. The food preparation chamber is provided by a container structureat least partly enclosing a receiving volume for receiving food to beprepared by a trough-streaming of hot air. The container structurecomprises side walls and a bottom wall. The bottom wall and/or one ofthe side walls is air-permeable providing an air entry opening forentering of hot air into the receiving volume. The container structurecomprises an air discharge opening. The heating device is configured toheat air of an air flow provided by the air movement device. The airguiding means provide an air duct arrangement from the discharge openingvia the heating device and the air movement device to the air entryopening. According to the still further aspect, a flow spreader isprovided between the air outlet and an air distributing zone providedbelow the air entry opening of the bottom wall. The flow spreader isprovided as a duct segment with a decreasing cross-section across an airpassage direction to compensate for an asymmetrical air output of theair outlet.

In a further example, the air duct wall for angled position is theouter, or lowest-positioned, air duct wall since this also supports tobend the air stream in a useful direction. The air duct becomes part ofthe air bent system and complies with the strategy to keep the total sumof bents below 360°.

The terms “bent” and “angle of the bent” in relation with the streamingdirection of hot air relates to the deviation or angular change of thedirection of the airflow in relation to the straight-forward direction.For example, if there is no bent, i.e. the air stream direction is notchanged, the angle would be referred to as an angle of 0°, a bent withan angle of 5° would relate to a slight change of the air streamdirection to the side. If the air stream is guided such that the airstream direction changes in a rectangular manner, this would be referredto as an angle of bent of 90°; a U-turn like deviation, or in otherwords air guidance in a reverse manner would be a bent with an angle of180°.

According to the present invention, also a method for preparing food ina desk-appliance apparatus is provided, comprising the following steps:In a first provision step, food is provided in a food preparationchamber provided by a container structure at least partly enclosing areceiving volume for receiving the food to be prepared. In a secondprovision step, a through-streaming of hot air is provided in the foodpreparation chamber. The through-streaming of hot air is provided by anair movement device and a heating device. A circulating air flow isprovided by air guiding means providing an air duct arrangement from adischarge opening of the container structure via the heating device andthe air movement device to an air entry opening of the containerstructure. The air is heated by the heating device that is arrangedout-of-sight of the receiving volume.

According to an aspect of the invention, an air-based fryer is providedwhere the heater is provided such that direct radiation of heat from theheater to the food inside the chamber is omitted and prevented. Thus,the heater only transfers heat to the air flow passing the heater,resulting in the air flow being the only heat source for heating thefood inside the food preparation chamber. Thus, a potential imbalance ofradiated heat and convected heat is also omitted, which means that theregulation of the provision the thermal energy and the air ventilation,or air flow, is facilitated.

According to a further aspect of the present invention, the resistanceof the flow path is minimized, aiming at a minimal some of all angles ofbents in the air recirculating system of maximum 360°. In one example,the outlet of the fan housing is provided such that the air exiting thefan has to make relatively smooth bents, or smooth air deviation, beforereaching a further air guide, which directs the air flow in the foodchamber. Due to the high air speed at these locations, the losses due toturbulence and friction are minimized, resulting in a relatively low airresistance and therefore a higher total flow rate and also a largerimpulse of the air that is entering the food via the air guide. In anexample, the fan is arranged such that the air has to change directionbefore entering the fan, but at this location, it is not critical,because the air speed is at least a little bit lower, and there is alsoa so-called under pressure or suction. It may be preferred to usesuction in this bent, with cross-sectional changes for example, sincethis may result in less turbulence and losses in comparison with blowingair through such bent.

These and other aspects of the present invention will become apparentfrom and be elucidated with reference to the embodiments describedhereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the invention will be described in thefollowing with reference to the following drawings:

FIG. 1 shows an example of a schematic cross-section of an apparatus forpreparing food with a heating device arranged out-of-sight of areceiving volume;

FIG. 2 shows a schematic cross-section of an example of an apparatus forpreparing food;

FIG. 3 shows further examples of a schematic cross-section of anapparatus for preparing food in a first example with a centrifugal faninside a scroll housing in FIG. 3A, in a second example with an axialfan in FIG. 3B, and a third example of a cross-flow blower in FIG. 3C;

FIG. 4 schematically shows a cross-section through a further example ofan apparatus for preparing food;

FIG. 5 shows examples of geometric relations in the context of aschematic cross-section of an apparatus for preparing food in FIGS. 5A,5B, and 5C;

FIG. 6 shows a schematic cross-section of a further example of anapparatus for preparing food with a collecting device below a foodpreparation chamber;

FIG. 7 shows a further example of an apparatus for preparing food withan air guide below an entry opening of a food preparation chamber in aschematic cross-section in FIG. 7A, and in a perspective view (notshowing the food preparation chamber and the air movement device, amongothers) in FIG. 7B;

FIG. 8 shows a cross-section of a further example of an apparatus forpreparing food with a flow spreader between an air movement device andan air distribution zone below the air entry opening of a foodpreparation chamber; and

FIG. 9 shows basic steps of a method for preparing food.

DETAILED DESCRIPTION OF EMBODIMENTS

FIG. 1 shows a desk-appliance apparatus 10 for preparing food. Theapparatus 10 comprises a food preparation chamber 12, an air movementdevice 14, a heating device 16, and air guiding means. It is noted thatthe air guiding means are indicated with dotted lines 18 in FIG. 1, incombination with arrows 20, schematically indicating an air flow. Thefood preparation chamber 12 is provided by a container structure 22 atleast partly enclosing a receiving volume 24 for receiving food to beprepared by a through-streaming of hot air. The receiving volume 24 isindicated with an upper dotted line. Further, the container structure 22comprises side walls 26 and a bottom wall 28. The bottom wall 28 and/orone of the side walls 26 is air-permeable providing an air entryopening, indicated with arrow 30, for entering of hot air into thereceiving volume. It is noted that the air entry opening 30 may beprovided across the whole surface of the bottom wall 28, or in selectedareas. Further, the container structure comprises an air dischargeopening, as indicated with upper arrow 32. The air discharge opening maybe provided by an opening across the whole upper surface, as shown inFIG. 1. The heating device 16 is configured to heat air of an air flowprovided by the air movement device 14. Further, the air guiding means18 provide an air duct arrangement 34 from the discharge opening 32 viathe heating device 16 and the air movement device 14 to the air entryopening 30.

FIG. 1 shows an example of an apparatus 10, wherein the heating device16 is arranged out-of-sight of a receiving volume 24. It must be notedthat the air movement device 14 is schematically shown. The air movementdevice 14 can be provided in different variations. Further, it must benoted that the heating device 16 can also be arranged in differentvariations, as long as a direct line of sight from the heating device 16to the receiving volume 24 is omitted, i.e. prevented.

For example, the heating device 16 is arranged sidewards of the foodpreparation chamber 12.

In an example, an air duct is provided between the outlet of the fan,e.g. a centrifugal fan, and the air entry opening of the bottom wall,which shall also be described in the following.

FIG. 2 shows a further example of the apparatus 10 for preparing food.The apparatus 10 comprises the food preparation chamber 12, the airmovement device 14, the heating device 16, and the air guiding means. Itis noted that the air guiding means are indicated with dotted lines 18in FIG. 2, in combination with arrows 20, schematically indicating anair flow. The food preparation chamber 12 is provided by the containerstructure 22 at least partly enclosing the receiving volume 24 forreceiving food to be prepared by a through-streaming of hot air. Thereceiving volume 24 is indicated with an upper dotted line. Further, thecontainer structure 22 comprises the side walls 26 and the bottom wall28. The bottom wall 28 and/or one of the side walls 26 is air-permeableproviding the air entry opening, indicated with arrow 30, for enteringof hot air into the receiving volume. It is noted that the air entryopening 30 may be provided across the whole surface of the bottom wall28, or in selected areas. Further, the container structure comprises theair discharge opening, as indicated with upper arrow 32. The airdischarge opening may be provided by the opening across the whole uppersurface, as shown in FIG. 2. The heating device 16 is configured to heatair of the air flow provided by the air movement device 14. Further, theair guiding means 18 provide the air duct arrangement 34 from thedischarge opening 32 via the heating device 16 and the air movementdevice 14 to the air entry opening 30.

The air movement device 14 is a fan 36 with an air inlet 38 and an airoutlet 40. The fan 36 is provided sidewards of the food preparationchamber 12. It is noted that according to the example shown in FIG. 2,the heating device 16 is provided sidewards of the food preparationchamber 12. However, also other examples can be provided, for exampleindicated with dotted circles 42, indicating a location of the heatingdevice 16 above the food preparation chamber 12.

According to an example, described in more detail below, the heatingdevice 16 is arranged out-of-sight of the receiving volume 24.

An outer frame structure indicates a possible housing enclosing theapparatus 10 for preparing food. Of course, the housing can be providedwith an insert opening for filling food into the food preparationchamber 12, which will also be described in more detail in relation withother figures below.

In FIG. 3, as an air movement device 14, a fan 44 is provided which hasan air suction side 46, and an air blowout side 48. It is noted thatnext to the air suction side 46, an arrow is shown indicating air beingsucked in on the air suction side. In use, the air is blown out at theair blowout side with a mean blowing direction 50. The mean blowingdirection 50 is provided with a tilted angle 52 to both the horizontaland the vertical. For example, the horizontal is referred to as ahorizontal portion 54 of a housing structure 55, and the vertical isreferred to as a vertical portion 56 of the housing structure 55.

FIG. 3A shows an example of the fan 44 as a centrifugal fan 58 with anaxial air inlet direction aligned with the arrow 46, and a radial airoutlet, aligned with the arrow 48. A line 60 is indicating an axis ofrotation.

FIG. 3B shows the fan 44 as an axial fan with an axial air inlet,aligned with arrow 46, and an axial air outlet, aligned with the arrow48. The axial fan 62 comprises a fan rotating around a rotating axis 64.The rotating axis 64 is provided with a titled angle to both thehorizontal and the vertical, similar to the tilted angle 52.

In an example, the fan 44 is provided sidewards of the food preparationchamber when the food preparation chamber is in use.

FIG. 3C shows the fan 44 in form of a cross-flow blower or cross-flowfan 66 with a rotating structure rotating around a rotating axis 68,i.e. a cylinder like structure that is perpendicular to the drawingplane.

FIG. 4 shows a further example, wherein the fan 44 is a centrifugal fan70 inside a fan housing with an axial air inlet 72 and a radial airoutlet 74. The centrifugal fan comprises a fan 76 rotating in a rotatingplane 78 around a rotating axis 80. The rotating plane 78 is providedwith a tilted angle, for example angle 82, to both the horizontal andthe vertical.

The centrifugal fan provides an integrated guiding of an air streamcoming from a first direction and leaving in a second direction, whereinthe second direction differs from the first direction by approximately30° to 120°, for example approximately 90°.

The tilted angle is provided such that a deflection or guidance of theair flow coming from the air movement device 14 is necessary in anamount of less than 90° in order to reach the area below the foodpreparation chamber 12. For example, the tilted angle comprises an angleto the horizontal in a range of approximately 10° to 80°. In an example,the angle is provided in a range of approximately 30° to 60°, forexample approximately 45°.

With references to FIGS. 5A, 5B, and 5C, geometrical relations of afurther example shall be explained in the following. The apparatus 10 isindicated by a rectangular frame 100, indicating a housing structure.Further, the food preparation chamber 12 is symbolically shown. Stillfurther, a first line 102 is defined by the rotating axis of acentrifugal fan, which is not further shown. A second line 104 isarranged perpendicular to the first line 102 in the rotating plane, asmentioned above. A third line 106 is perpendicular to the bottom wall 28and running through a centre of the bottom wall 28. The first line 102,the second line 104, and the third line 106 are arranged in one planeand form a triangle 108 provided by a first section 110 of the firstline 102, the first section 110 extending from the intersection of thefirst line 102 with the second line 104 to the intersection of the firstline 102 with the third line 106. The triangle 108 is further defined bya second section 112 of the second line 104, the second section 112reaching from the intersection of the second line 104 with the firstline 102 to the intersection of the second line 104 with theintersection of the third line 106. As a third side of the triangle 108,a third section 114 of the third line 106 is defined, the third section114 extending from an intersection of the third line 106 with the firstline 102 to an intersection of the third line 106 with the second line104. An inner circle 116 of the triangle 108 is arranged inside thehousing structure 100 of the apparatus. The first and the second linehave an intersection point 118 that is arranged in a middle region ofthe height of the housing structure. The height is indicated with adouble arrow 120. According to the invention, the inner circle 116 has amaximum diameter 122.

The “middle region” relates to a height arranged in the middle third ofthe height. The arrangement of the intersection in the middle of theheight allows a maximum diameter of a fan, e.g. a centrifugal fan.

FIG. 5B shows a further possible arrangement of the first line 102, thesecond line 104, and the third line 106, wherein the first line 102 andthe second line 104 are maintained perpendicular to each other, buttilted together in relation to the third line 106, namely approximately10° to 30° in a clockwise direction. For a better understanding, a firstdotted line 124 indicates the position of the first line 102 of FIG. 5A,and a second dotted line 126 indicates the position of the second line104 of FIG. 5A. The first line 102, the second line 104, and the thirdline 106 form a triangle, however with different proportion compared toFIG. 5A. An inner circle of the triangle with a maximum diameter isindicated by a dotted circle 128. However, this inner circle 128 wouldextend outside of the housing structure 100. Thus, an inner circle ofthe triangle arranged inside the housing structure 100 would have tosmaller, as indicated with a full line circle 130.

FIG. 5C shows a further example, in which the first line 102 and thesecond line 104, being perpendicular to each other, are slightly rotatedcounter-clockwise, leading to a similar situation, in which the circle130, i.e. the dotted circle, indicates the inner circle of the triangle,but the circle 128 in straight line shows the maximum diameter of acircle arranged inside the housing structure 100 and as an inner circleof the triangle.

Thus, in order to provide the inner circle with a maximum diameter, thedegree of angulations of the triangle should be well balanced byproviding the first and the second lines 102, 104 with approximately 45°to both the horizontal and the vehicle.

With reference to FIG. 4, some further examples are described. Asindicated by two lines 138, an air duct arrangement comprises a numberof guiding portions, in which an air flow direction is changed. It isnoted that air guiding portions are also provided by housing parts orelements not further shown in detail which is why they are not labelledwith a reference number. For a better understanding, a simplifiedcirculating air flow 140 is indicated. For example, hot air exiting fromthe air movement device 14 is slightly changing its direction due to theguiding portion 138. Further, the air flow is changing its directionbelow the bottom wall 28, as indicated with bending portion 140.Following, the air flow streams through food to be prepared and uponexiting the food, i.e. at the air discharge opening 32, a further changeof direction, as indicated by a further bending portion 144, isprovided. Upon reaching a portion above the side walls, a furtherbending portion 146 indicates a further guiding portion. Still further,a bending portion 148 arranged inside the air movement device 14indicates that a further change of airflow direction is provided.

According to an example, a first guiding portion, for example theguiding portion 138, is provided downstream, following the air movementdevice 14, and a second guiding portion, for example the guiding portion146, is provided upstream in front of the air movement device 14. Thefirst guiding portion 138 provides a lower degree of change of directionof the air flow than the second guiding portion 146.

For example, the guiding portion with the sharpest bent for the air flowis provided at the suction side of the air movement device, e.g. thefan. The least sharp bent is provided near the air movement deviceoutlet.

In an example, from all guiding portions of the air duct arrangement,the second guiding portion provides a maximum degree of change ofdirection of the air flow, and the first guiding portion provides aminimum degree of change of direction of the air flow.

Preferably, the guiding portions are providing minimum number of bentsfor a maximum air flow, i.e. providing minimized air flow resistance. Inan example, the air duct arrangement is provided with guiding portionsthat provide a sum of bents of approximately 360°.

In a further example, also shown in relation with FIG. 4, the housingstructure 100 comprises an upper opening 150 for inserting the containerstructure 22 from a top. A cover device 152, for example a lid, isprovided for closing the opening 150 during food preparation. Forexample, the container structure 22 is provided as a removable pot orbasket 154 with a handle bar or a grip portion 156 for easier handling.

In a further example, also indicated in relation with FIG. 4, sensormeans 160 are provided in relation with the air movement device 14 fordetecting air temperature of the air stream supplied by air movementdevice 14. For example, the sensor means 160 are sensors arranged insidea housing structure of the air movement device 14. The sensor means mayalso be provided downstream the air movement device between the airoutlet and the bottom wall of the container structure. The sensors candetect if the air heated by the heating device gets too hot, due to amalfunction of the heating device, for example.

According to a further example, also shown in relation with FIG. 4, aremovable pan structure 170 is provided at least partly below the foodpreparation chamber. For example, the food preparation chamber 12 is atleast partly inserted into the removable pan structure 170. Anair-guiding duct 172 is provided between the removable pan structure 170and the bottom wall 28. The air-guiding duct 172 is provided for guidingheated air stream from the air outlet, for example the radial air outlet74, to the air entry opening 30.

The air-guiding duct is provided by the removable pan structure and thebottom wall as the physical features; the food preparation chamberrelates to the space or area defined by the container walls that areenclosing the food preparation chamber at least partly.

In an example, the removable pan structure is provided as one removablepan. In another example, two or more removable pans are provided.

In a further example, a non-removable pan structure is provided, forexample a pan fixed to the housing, and a separately removable small oiland particle collection container is provided.

It must be noted that although FIG. 4 shows the different aspectsdescribed above in a single embodiment, it is provided that, forexample, the aspect of the guiding portions, the aspect of the sensormeans, the aspect of the centrifugal fan, the aspect of the removal panstructure can be provided in combination with the respective otherfeatures, or also without the respective other features, i.e. indifferent varying combinations.

Before referring to the following figures showing further embodiments,some general aspects of the present invention shall be described in thefollowing.

The term “out-of-sight” relates to an arrangement where a direct(linear) line between the heating device and the receiving volume, i.e.in particular the food arranged in the receiving volume, is notpossible, because the direct connection line is blocked by otherstructural parts.

The thermal energy provided by the heating device is predominantlytransferred via heat convection. The air flow is transporting andtransmitting the thermal energy to the food to be prepared. However,some of the radiation from the heating device may be reflected by thelid, for example. Nevertheless, the resulting energy flow in form ofthis radiated heat is much lower than the convection part. For example,the heating device is arranged in a concealed manner with respect to thefood being prepared. In one example, a side wall shades off radiatedheat from the heating device with respect to the receiving volume, i.e.the side wall is a barrier with respect to direct line of connectionbetween the heating device and the receiving volume. This avoids thatthe food is heated by direct radiation from the heating device, but onlyby heat provided by the generated heated air. Nevertheless, a reflectoron top of the food may be provided for an improved use of the thermalenergy provided to the food by the heated air. The receiving volume doesnot experience any heat transfer by direct radiation from the heatingdevice.

The “air movement device” is also referred to as a fan device or aventilation device. The air movement device provides movement of heatedair in a circulating fashion for heating the food to be prepared. Theair movement device provides movement of the air without varying otherair parameter, in one example. In another example, the air movementdevice also provides influencing or adjusting other airproperties/parameters, such as humidity, oxygen content, ratio of reusedair and fresh air input, for example. The heated air may be provided tofood having different insertion temperatures. For example, in case ofapplying heated air to frozen fries, the resulting air flow may be atemperature below 0° C., at least for the first time span, e.g. for thefirst 10 to 30 seconds, since the thermal energy provided to the heatedair by the heater is nearly completely transferred to the frozen fries.At the end of the food preparing process, the air temperature may reach140° C. to 200° C. or more. The air temperature may be adjustable,depending on the type of food.

The container structure may enclose the food preparation chamber partlyin form of a pot or pan by providing a bottom wall and a surroundingcontinuous side wall, or a number of side walls.

The container structure may enclose the food preparation chambercompletely in form of a closed pot or pan by providing not only a bottomwall and a side wall, but also a closing upper structure such as a lidor cover.

In any case, provisions are taken to let a stream of heated air enteringthe food preparation chamber, i.e. via the air entry opening, and alsoto let the air exiting the food preparation chamber, i.e. via the airdischarge opening.

The term “opening” in relation with the air stream relate to thecapability of air passing through. This may be provided, for example, bya sieve, grid, or mesh-like structure. The term “heated air” relates toair heated up to temperature range of approximately 80 to 200° C. at theend, or the temperature peak, of the food preparation process. The airmay be provided with different amounts of relative humidity. Forexample, a relative humidity range of 5 to 100% may be provided.

The term “sidewards of the food preparation chamber” refers to anarrangement of the air movement device on the side or besides the foodpreparation chamber in a horizontal direction. For example, the airmovement device is located next to side walls of the food preparationchamber. The air movement device may also be located sidewards in ahorizontal direction and displaced upwards, such that the air movementdevice extends above the container structure.

The term “the horizontal” relates to a horizontal plane or axis, when innormal operation. The term “the vertical” relates to a respectivevertical plane or axis.

For example, the term horizontal relates to a desk surface or workingsurface, for example in a kitchen. In another example, the term verticalrelates to a perpendicular line with regard to the horizontal.

For example, the air discharge opening 32 is provided by side wallportions of the container structure 22. In an example, the dischargeopening 32 is provided as an upwardly oriented opening of the containerstructure 22. In another example, the discharge opening 32 is providedby side wall portions of the container structure 22.

The term “bottom wall” refers to a wall segment or wall area provided inthe lower part, facing downwards in a normal operation state. The term“side walls” also refers to a side wall arrangement with a continuousside wall or a plurality of side wall segments.

In relation with the centrifugal fan, the term “axial air inlet” relatesto an air inlet or suction opening of the air movement device, forexample provided in the vicinity of the rotating axis of the centrifugalfan, or in the vicinity of the rotating axis of an axial fan. In case ofa centrifugal fan, the air inlet may be provided between the rotatingaxis and the circumference described by rotating blades (or vanes) ofthe centrifugal fan.

In an example, the air movement device is provided downstream of theheating device. In another example, the heating device is provideddownstream of the air movement device. In a further example, heating isprovided upstream and downstream of the air movement device.

The air outlet may be provided as a radial air outlet, as alreadymentioned above. However, the air may be blown out also with atangential movement component.

In an example, the receiving volume 24 is a sub-volume (i.e. a part ofthe volume) of the food preparation chamber 12.

The tilted arranged of the air movement device 14 provides the effectthat a circulating part of the air flow is provided with a minimizeddegree of bents of the air duct or air path, and the sharpest bent islocated at the air inlet of the fan. This means a minimized resistancefor the air flow, and thus improves the air flow rate.

FIG. 6 shows a further example, wherein a collecting device 180 with acollection volume 182 is provided below the food preparation chamber 12for collecting residual material. The term “residual material” refersto, for example, oil, and particles.

In a further example, an air guiding element 184 is provided thatdirects a horizontal air flow 186 below the container structure 22 in anupwards direction towards the air entry opening 30. The collectingdevice 180 is arranged besides the air guiding element 184 on a side 188facing away from the horizontal air flow 186.

The collecting device 180 is arranged on the leeside of the air guidingelement, i.e. the air guiding element is providing shading of the heatedair stream. In an example, the collecting device is provided by at leastone recess in the removable or detachable pan. In an example, the recessin the removable pan is provided with a drainage opening, and aremovable collecting receptacle is provided below the opening (notfurther shown).

In a further example, the collecting device is provided as a separateinlay placed into a recess of the removable pan (also not furthershown).

FIG. 7 shows a further example in a cross-section in FIG. 7A, and aperspective view in FIG. 7B. An air-distributing duct 190 is providedbelow the air entry opening 30 of the bottom wall 28. An air guide 192is provided as an elevation arranged on a lower surface 194 of the airdistributing duct 190 below the air entry opening 30. For example, theelevation is extending across the cross-section of the air distributingduct 190. In an example, the elevation is extending across at least athird of the cross-section, for example in one section or also inseparated sections. In a further example, the elevation is extendingacross at least half of the cross-section. For example, as shown, theelevation is extending across the whole width of the cross-section, asshown in FIG. 7B. The air guide 192 is arranged in a skewed manner,indicated with an angle 196 between the linear extension indicated witha first dotted line 198, and a perpendicular (or rectangular angle ofthe general or mean direction of the air distributing duct, whichperpendicular is indicated with a second dotted line 200. The air guideis arranged in the skewed manner 196 in relation to a perpendiculardirection of an out-blowing direction of an air outlet such that belowthe air entry opening 30, an evenly distributed air flow is provided.This is indicated with three air stream indicating arrows 202 in FIG.7B.

The “skewed manner” relates to an angle of at least 5° or 10° to theperpendicular direction of the out-blowing direction. The “out-blowingdirection” relates to a central air flow direction of the blown out airstream.

The elevation may be extending over the complete cross-section of thewidth, as mentioned above, or also only over a part. Further, the airguide 192 can be provided as linear air guide, as shown. In anotherexample (not shown), the air guide is provided in a curved manner.

FIG. 8 shows a further example, wherein a flow spreader 210 is providedbetween the air outlet 212 of the air movement device 14 and an airdistribution zone 214 provided below the air entry opening 30 of thebottom wall 28. The flow spreader is provided as a duct segment 216 witha decreasing cross-section, indicated with double arrow 218, across anair passage direction to compensate for an asymmetrical air output ofthe air outlet. The flow spreader is provided as an inclined wall of anair duct. For example, the bottom wall segment is inclined in relationto the horizontal. In an example, a rip structure is provided in theduct segment 216. For example, the inclined wall has a tilted angle inrelation to the horizontal that is smaller than the tilted angle of therotating plane in relation with the horizontal. For example, a firstangle 220 indicates the angle of the rotating plane in relation with thehorizontal, and a second angle 222 indicates an angle of the inclinedwall, for example wall segment 224, with the horizontal. As can be seen,the second angle is smaller than the first angle.

FIG. 9 shows an example of a method 300 for preparing food in adesk-appliance apparatus, comprising the following steps: In a firststep 302, food is provided in a food preparation chamber provided by acontainer structure at least partly enclosing a receiving volume forreceiving the food to be prepared. In a second step 304, athrough-streaming of hot air is provided in the food preparationchamber. The through-streaming of hot air is provided by an air movementdevice and a heating device. A circulating air flow is provided by airguiding means providing an air duct arrangement from the dischargeopening of the container structure via the heating device and the airmovement device to an air entry opening of the container structure. Theair is heated by the heating device that is arranged out-of-sight of thereceiving volume.

The first step 302 is also referred to as step a), and the second step304 as step b).

For the air movement, a fan with an air inlet and an air outlet isprovided, wherein the fan is provided sidewards of the food preparationchamber in a further example.

It must be noted that further examples of the method are provided inrelation with the above-mentioned features of the different embodiments.

It has to be noted that embodiments of the invention are described withreference to different subject matters. In particular, some embodimentsare described with reference to method type claims whereas otherembodiments are described with reference to the device type claims.However, a person skilled in the art will gather from the above and thefollowing description that, unless otherwise notified, in addition toany combination of features belonging to one type of subject matter alsoany combination between features relating to different subject mattersis considered to be disclosed with this application. However, allfeatures can be combined providing synergetic effects that are more thanthe simple summation of the features.

While the invention has been illustrated and described in detail in thedrawings and foregoing description, such illustration and descriptionare to be considered illustrative or exemplary and not restrictive. Theinvention is not limited to the disclosed embodiments. Other variationsto the disclosed embodiments can be understood and effected by thoseskilled in the art in practicing a claimed invention, from a study ofthe drawings, the disclosure, and the dependent claims.

In the claims, the word “comprising” does not exclude other elements orsteps, and the indefinite article “a” or “an” does not exclude aplurality. A single processor or other unit may fulfil the functions ofseveral items re-cited in the claims. The mere fact that certainmeasures are re-cited in mutually different dependent claims does notindicate that a combination of these measures cannot be used toadvantage. Any reference signs in the claims should not be construed aslimiting the scope.

The invention claimed is:
 1. A desk-appliance apparatus for preparingfood, comprising: a food preparation chamber; an air movement device; aheating device; and air guiding means, wherein the food preparationchamber includes a removable container structure that at least partlyencloses a receiving volume for receiving food to be prepared by athrough-streaming of hot air, wherein the removable container structurecomprises sidewalls and a bottom wall, wherein at least the bottom wallof the removable container structure is air-permeable for providing anair entry opening for an entering of hot air into the receiving volume,wherein the entering of hot air into the receiving volume of theremovable container structure facilitates the through-streaming of thehot air into the food received within the receiving volume, and whereinthe removable container structure further comprises an air dischargeopening in a top of the removable container structure, wherein theheating device is arranged out-of-sight of the receiving volume andconfigured to heat air of an air flow provided by the air movementdevice, wherein the air guiding means include an air duct arrangementconfigured to guide air (i) from the air discharge opening of theremovable container structure via the heating device and the airmovement device and (ii) to the air entry opening of the removablecontainer structure, wherein the air duct arrangement further includesan air distributing duct below the air entry opening of the bottom wallof the removable container structure, wherein the air distributing ductincludes an air guide that comprises an elevation arranged on a lowersurface of the air distributing duct below the air entry opening of thebottom wall of the removable container structure, and wherein the airguide is arranged in a skewed manner in relation to a perpendiculardirection of an out-blowing direction of an air outlet of the airmovement device such that an evenly distributed air flow is providedbelow the air entry opening of the bottom wall of the removablecontainer structure.
 2. The apparatus according to claim 1, wherein theheating device is arranged sidewards of the food preparation chamber. 3.The apparatus according to claim 1, wherein the air movement device is afan with an air inlet and an air outlet; and wherein the fan is providedsidewards of the food preparation chamber.
 4. The apparatus according toclaim 1, wherein the air movement device comprises a fan that includesan air suction side and an air blowout side, wherein, during operationof the fan, air is blown out at the air blowout side with a mean blowingdirection, and wherein the mean blowing direction includes a tiltedangle to both a horizontal and a vertical of the desk-applianceapparatus.
 5. The apparatus according to claim 3, wherein the fan is acentrifugal fan with an axial air inlet and a radial air outlet, whereinthe centrifugal fan comprises a fan blade configured to rotate in aplane of rotation, and wherein the plane of rotation includes a tiltedangle to both a horizontal and a vertical of the desk-applianceapparatus.
 6. The apparatus according to claim 4, wherein the tiltedangle comprises an angle to the horizontal in a range of approximately10° to 80°.
 7. The apparatus according to claim 1, further comprising: ahousing structure with a height, and wherein: a first line is defined byan axis of rotation of the air movement device, a second line isarranged perpendicular to the first line in a plane of rotation of theair movement device, and a third line is perpendicular to the bottomwall of the removable container structure and through a centre of thebottom wall, wherein the first line, the second line and the third lineare arranged in one plane and form a triangle, and wherein an innercircle of the triangle is arranged inside the housing structure, whereinthe axis of rotation and the plane of rotation of the air movementdevice are configured such that the first and the second line have anintersection point that is arranged in a middle region of the height ofthe housing structure; and wherein the inner circle has a maximumdiameter within the housing structure.
 8. The apparatus according toclaim 1, wherein an air duct arrangement comprises a number of guidingportions, in which an air flow direction is changed; wherein a firstguiding portion is provided downstream following the air movementdevice, and a second guiding portion is provided upstream in front ofthe air movement device; and wherein the first guiding portion providesa lower degree of change of direction of the airflow than the secondguiding portion.
 9. The apparatus according to claim 1, furthercomprising: sensor means, in relation with the air movement device, fordetecting air temperature of an airstream supplied by the air movementdevice.
 10. The apparatus according to claim 1, further comprising: aremovable pan structure into which the food preparation chamber is atleast partly inserted, wherein the removable pan structure is below thefood preparation chamber, under the removable container structure, andwherein the removable pan structure forms an air-guiding duct between(i) the removable pan structure and (ii) the bottom wall of theremovable container structure for guiding a heated air stream from anair outlet of the air movement device to the air entry opening of theremovable container structure.
 11. The apparatus according to claim 1,further comprising: a collecting device with a collection volume,wherein the collecting device is located below the food preparationchamber, under the removable container structure, for collectingresidual material.
 12. The apparatus according to claim 11, wherein theair duct arrangement further includes an air-guiding element thatre-directs a horizontal air-flow below the removable container structureinto an upwards direction towards the air entry opening of the removablecontainer structure, and wherein the collecting device is arrangedbesides the air-guiding element on a side facing away from thehorizontal air-flow.
 13. The apparatus according to claim 1, furthercomprising: a flow spreader between (i) an air outlet of the airmovement device and (ii) an air distribution zone below the air entryopening of the bottom wall of the removable container structure, whereinthe flow spreader comprises a duct segment with a decreasingcross-section across an air passage direction to compensate for anasymmetrical air output of the air outlet of the air movement device.14. A method for preparing food via a desk-appliance apparatus, themethod comprising: a) providing a food preparation chamber that includesa removable container structure that at least partly encloses areceiving volume for receiving food to be prepared by a through-steamingof hot air; and b) providing the through-streaming of hot air in thefood preparation chamber via an air movement device, a heating device,and an air guiding means, wherein the removable container structurecomprises sidewalls and a bottom wall, wherein at least the bottom wallof the removable container structure is air-permeable for providing anair entry opening for an entering of hot air into the receiving volume,wherein the entering of hot air into the receiving volume of theremovable container structure facilitates the through-streaming of thehot air into the food received within the receiving volume, wherein theremovable container structure further comprises an air discharge openingin a top of the removable container structure, wherein the heatingdevice is arranged out-of-sight of the receiving volume and configuredto heat air of an air flow provided by the air movement device, whereina circulating air flow is provided by the air guiding means thatincludes an air duct arrangement configured to guide air (i) from thedischarge opening of the removable container structure via the heatingdevice and the air movement device and (ii) to the air entry opening ofthe removable container structure wherein the air duct arrangementfurther includes an air distributing duct below the air entry opening ofthe bottom wall of the removable container structure, wherein the airdistributing duct includes an air guide that comprises an elevationarranged on a lower surface of the air distributing duct below the airentry opening of the bottom wall of the removable container structure,and wherein the air guide is arranged in a skewed manner in relation toa perpendicular direction of an out-blowing direction of an air outletof the air movement device such that an evenly distributed air flow isprovided below the air entry opening of the bottom wall of the removablecontainer structure.